The Guaracara River, located in south Trinidad

Trinidad

Trinidad is the larger and more populous of the two major islands and numerous landforms which make up the island nation of Trinidad and Tobago. It is the southernmost island in the Caribbean and lies just off the northeastern coast of Venezuela. With an area of it is also the fifth largest in...

, runs westward out of the Central Range and drains into the Gulf of Paria

Gulf of Paria

The Gulf of Paria is a shallow inland sea between the island of Trinidad and the east coast of Venezuela. This sheltered body of water is considered to be one of the best natural harbours on the Atlantic coast of the Americas...

. It forms the boundary between the city of San Fernando

San Fernando, Trinidad and Tobago

The City of San Fernando with a population of 55,419 according to the 2000 census, is the larger of Trinidad and Tobago's two cities and the second largest municipality after Chaguanas. It occupies 18 km² and is located in the southwestern part of the island of Trinidad...

 (to the south) and the Couva-Tabaquite-Talparo Regional Corporation

Couva-Tabaquite-Talparo Regional Corporation

Couva-Tabaquite-Talparo Regional Corporation is a Regional Corporation of Trinidad and Tobago. It has a land area of 719.64 km². Urban areas within Couva-Tabaquite-Talparo Regional Corporation include Claxton Bay, Couva, Point Lisas, St...

. In local terms it separates Marabella

Marabella

Marabella is a former town in southern Trinidad, between San Fernando and Pointe-à-Pierre . Originally a separate town, it was incorporated into the City of San Fernando in the 1990s....

 (the northernmost portion of the city) from Pointe-à-Pierre

Pointe-à-Pierre

Pointe-à-Pierre is a town in Trinidad and Tobago. It lies north of San Fernando and south of Claxton Bay. It is most famous as the site of the country's largest oil refinery which is run by Petrotrin, the state-owned oil company....

.

The river

River

A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...

 is heavily polluted, both by non-point agricultural and residential run-off from Marabella and the town of Gasparillo

Gasparillo

Gasparillo is a town in southern Trinidad. It lies east of Pointe-à-Pierre and northeast of San Fernando. The population is approximately 16,000. The name Gasparillo is applied not only Gasparillo proper, but also the surrounding communities including Bonne Aventure and Whiteland. Trinidadians do...

, and from industrial waste (primarily oily run-off) from the oil refinery

Oil refinery

An oil refinery or petroleum refinery is an industrial process plant where crude oil is processed and refined into more useful petroleum products, such as gasoline, diesel fuel, asphalt base, heating oil, kerosene, and liquefied petroleum gas...

 at Pointe-a-Pierre owned by Petrotrin

Petrotrin

Petrotrin, the Petroleum Company of Trinidad and Tobago is the major State-owned oil company in Trinidad and Tobago. The company was established in 1993 by the merger of Trintopec and Trintoc, two state-owned oil companies. A third company, Trinmar was later merged into the company...

(the State-owned oil company).